Oh, man, we seem to have been cross-posting more than once this thread - sorry if my notes seem out of sequence!
To measure primary resistance, pull the power plug from the wall socket. Insert a new fuse (sorry about all the fuses!) Connect one lead of the ohm meter to one blade of the power plug. Connect the other lead of the ohm meter to the other blade of the power plug. Ignore the round pin on the power plug. (I assume you are using US-type power cord...). Switch the amp on. Read the meter.
But from your last post, it's just what I was afraid of - the label is on the transformer backwards. Make the primary resistance measurement as above, and if it shows a low resistance (less than 1 ohm) then the theory above is confirmed.
Assuming that's the case, pull the PSU board off the transformer - again - and throw it away, then rotate the transformer and see if you can't rotate the label too. The transformer is almost certainly just fine, the fuse has protected it. However, removing and re-installing the PSU board is hard on the board and I think you should just replace it. Email Eileen Monday and tell her PJ said we owe you a new PSU board with all the parts.
We apologize for the annoyance - we really do feel bad when this happens.
